Combination shearing and shut-off ram for blowout preventer

ABSTRACT

A ram block is carried by ram holders in each of two ram assemblies in ram-receiving chambers within a blow-out preventer. One ram block is provided with a downwardly opening recess formed to accommodate a seal member on the lower side thereof but spaced from a diametrical open side of the ram block. The other ram block is provided with a shearing blade projecting from a diametrical open side of the second ram block holder and adapted to coact with the first ram block to shear a drill string and after the shearing action to sealingly engage the seal member of the first ram block when the rams are moved to the closed position.

Vujasinovic 14 1 June 5, 1973 [541 COMBINATION SHEARING AND SHUT-3,379,255 4/1968 Burns et a1. ..166/55 OFF RAM FOR BLQWOUT- 3,561,5262/1971 Williams et a1 v.166/55 PREVENTER P E D d H rimary xaminer aviBrown [75] Inventor Ado Houston Attorney-James F. Weller, Jefferson D.Giller and [73] Assignee: The Rucker Company, Houston, Dudley ,-l 6tTex.

[57] ABSTRAT [22] Filed: May 1, I972 A ram block is carried by ram.holders in each of two PP N05 249,291 ram assemblies in ram-receivingchambers within a blow-out preventer. One ram block is provided with a[521 LS Cl H 166/55 251/1 downwardly opening recess formed toaccommodate a [51] Int CL E21629/00 seal member on the lower sidethereof but spaced [58] Fie'ld 55 1 63 from a diametrical open side ofthe ram block. The 1 other ram block is provided with a shearing bladeprojecting from a diametrical open side of the second ram [56]References Cited block holder and adapted to coact with the first ramblock to shear a drill string and after the shearing ac- UNITED STATESPATENTS tion to sealingly engage the seal member of the first ram blockwhen the rams are moved to the closed 2,969,838 1/1961 Wilde ..166/55position 2,919,111 12/1959 Nicolson ..l66/55 X 18 Claims, 9 DrawingFigures 6 5 74 34 69 s2 48 5 so 38 4o 46 l as 84 "L 68 1 Patented June5, 1973 3 Sheets-Sheet 1 Patented June 5, 1973 3 Sheets-Sheet 5COMBINATION SHEARING AND SHUT-OFF RAM FOR BLOWOUT PREVENTER BACKGROUNDOF THE INVENTION The present invention relates generally to blowoutpreventers forming a part of well drilling equipment as used, forexample, in the drilling of oil wells and gas wells. Typical of suchblowout preventers are those disclosed in the following US. Pats.: No.2,969,838, granted Jan. 31, 1961 to Arthur E. Wilde, No. 3,561,526,granted Feb. 9, 1971 to Williams et al., and No. 3,590,920, granted July6, 1971 to Orund et al.

Generally speaking, as is well known to those skilled in the art,instances arise wherein a drill string must be cut and/or sealed toprevent damage to the well and associated equipment. This isparticularly true in offshort drilling operations.

Conventional devices for shearing a drill string and shutting off a wellare effective but suffer the disadvantage of requiring manipulation ofdrill pipes to complete sealing of the well once the pipe has been cut.For example, in the embodiments of the patents cited above, at least theupper portion of the drill pipe remains in a flattened condition clampedbetween face seals of ram blocks after being sheared. In such position,the face seals of the ram are unable to mate until the cut drill pipehas been pulled from between the rams. The added manipulation requiredin order to move the drill pipe from between the rams poses a problemwhich can be particularly serious in emergency situations.Advantageously, the present invention overcomes the disadvantage ofhaving to retrieve the upper portion of the cut drill pipe through theprovision of a shearing blade arrangement wherein the blade itself actsto form a seal between the rams.

SUMMARY OF THE PRESENT INVENTION The present invention is directed to animprovement in blowout preventers of the type having shearing andshut-off rams. The blowout preventer has a body member housing first andsecond ram assemblies, each ram assembly having a ram block holder and aram block with a seal therebetween.

In the improvement of the present invention, one of the ram blocks isprovided with a downwardly opening recess formed on the lower sidethereof along and spaced from a diametrical open side of the ram block.A seal member is disposed within the recess to sealingly engage ashearing blade member secured to and projecting from the opposed ramblock holder of the other ram assembly. Consequently, it is notnecessary that the faces of the two ram blocks of the respective ramblock assemblies meet when the ram assemblies are closed since a seal iseffected between the shearing blade of one ram block and the seal memberin the recess of the other ram block-Thus the sheared drill pipe neednot be manipulated or retrieved in order for the blowout preventerdevice to seal the well.

It is, therefore, an object of the present invention to provide animproved shearing and shut-off ram system for a blowout preventer foruse in the drilling of wells.

Yet a further object of the present invention is the provision of suchan improved assembly wherein a drill pipe may be sheared and the wellsealed by coaction of a shearing blade with a ram block seal to obviatemanipulation of the drill pipe or rams to effect a complete closure.

A still further object of the present invention is the provision of suchan improved blowout preventer device wherein the seal effected between ashearing blade and a seal member of an opposing ram block isstrengthened by virtue of lateral movement of the shearing bladerelative to the opposing ram block in order to compress the seal memberthat engages the shearing blade.

Other and further objects, features and advantages will be apparent inthe following description of preferred embodiments of the invention,given for the purpose of disclosure and taken in conjunction with theaccompanying drawings.

DESCRIPTION OF THE DRAWINGS In the drawings forming a part of thedisclosure herein, like character references designate like partsthroughout the several views, wherein,

FIG. 1 is a partial elevation view, partly in cross section, showing ablowout preventer and ram assembly according to the present invention,

FIG. 2 is a view similar to that of FIG. 1 wherein the shearing and ramassembly has been actuated to cut a drill pipe within the blowoutpreventer,

FIG. 3 is a plan view of ram assemblies according to the presentinvention,

FIG. 4 is a cross-sectional view of the ram assemblies according to thepresent invention, taken along the line- 4-4 of FIG. 3,

FIG. 5 is a view similar to that of FIG. 4 but showing the ramassemblies in a closed or engaged position,

FIG. 6 is a partial cross-sectional view of one embodiment of a sealmember within the lower recess of a ram block,

FIG. 7 is a partial cross-sectional view of yet a further embodiment ofsuch a seal,

FIG. 8 is a partial cross-sectional view of still another embodiment ofa seal, and

FIG. 9 is a perspective view of ram assemblies of the blowout preventerof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, adouble cellar control gate or blowout preventer 10 is illustrated havingan upper shear ram assembly 12 and a lower pipe ram assembly 14. Thediscussion herein will relate primarily to the shear ram assembly 12inasmuch as the pipe ram assembly 14 may be of conventional design wellknown to those skilled in the art.

With reference to FIG. 1 as well as to FIG. 2, the control gate has abody 16 with a vertical bore 18 therethrough for reception of a drillstring 20. The body member 16 is provided with opposed ram-receivingchambers 22 and 24 in a plane normal to the bore 18.

Referring also to FIG. 9, a first ram assembly 26 is provided forinsertion within one of the ram-receiving chambers such as the chamber24. The first ram assembly 26 generally comprises a ram block holder 28of semi-circular configuration having a substantially concentric,semi-circular, upwardly opening recess 30 on the upper side. Securedwithin the recess 30 is a semicircular ram block 32. A seal member 34 isdisposed along and between at least the circular portions of the ramblock holder 28 and the ram block 32.

A second ram assembly 36 (as best shown in FIG. 9) is provided to beinserted within the ram-receiving chamber 22. The second ram assembly 36generally comprises a ram block holder 38 of semi-circular configurationsimilar to that of the ram block holder 28. A semi-circular ram block 48is secured within a recess 42 of the holder 38, the recess 42 beingsimilar to the recess 30 of the ram assembly 26. A shearing blade member44 is secured to and is projectingly disposed along the diametrical openside of the ram block holder 38 and is adapted to coact with the ramblock 32 of the first ram assembly 26 to shear a drill string and isfurther adapted after such shearing action to sealingly engage a sealmember of the first ram assembly 26 as will be described hereafter. Aseal member 46 is disposed along and at least between the circularportions of the holder 38 and the ram block 40.

With reference to FIGS. 3 and 4, the first ram assembly 26 includes aram block holder 28 of semi-circular configuration having asubstantially concentric, semicircular, upwardly opening recess 30 onthe upper side. A semi-circular ram block 32 is secured such as by abolt 33 within the recess of the holder 28. The ram block 32 is providedwith a downwardly opening recess 48 formed on its lower side but spacedfrom the diametrical open side 50 of the ram block 32.

Preferably, the ram block of the first ram assembly 26 is formed of twopieces secured together as shown in FIGS. 3 and 4, including the mainram block portion 32 and a face plate 52 secured to the main ram blockportion 32 by a series of bolts 54. As best shown in FIG. 4, the faceplate 52 coacts with the main portion of the ram block 32 in forming therecess 48. Consequently, in the downwardly opening, substantiallylongitudinal recess 48 formed on the lower side of the ram block 32, thewall 56 of the recess 48 nearest the diametrical open side 50 of the ramblock 32 tapers outwardly and downwardly as shown.

A seal member 34 is disposed along and between at least the circularportions of the ram block holder 28 and the ram block 32 of the firstram assembly 26. The seal member 34 preferably is formed of resilientmaterial such as rubber in a half-ring configuration as shown in FIG. 3and has a half-ring reinforcing bar 58 embedded in the resilientmaterial yet preferably exposed on one side 60 for engagement with theram block 32.

A second seal member 62 is disposed within the downwardly opening recess48 of the ram block 32, the

' seal member 62 being of a configuration substantially conforming tothe configuration of the recess 48. Preferably, the seal member 62 isformed of a resilient material such as rubber and is at least as long asthe shearing blade member 44 of the second ram assembly 36 as shown inFIG. 3. It is also preferred that the resilient portion of the seal 62be formed integrally with the first seal member 34 to insure againstfluid leakage between the ram block 32 and the holder 28. The sealmember 62 is mounted within the recess 48 so as normally to besubstantially flush with the lower surface 64 of the ram block 32. Anelongate (approximately as long as the resilient material) metalsupporting plate 66 is molded by suitable means in the strip ofresilient material forming the seal 62, the supporting plate 66 beingadapted to pressingly engage the shearing blade 44 when the ramassemblies 26 and 36 are moved to the closed position as will beexplained.

As best shown in FIG. 4, a portion 68 of the resilient material formingthe seal 62 is disposed between the elongate metal supporting plate 66and the wall 56 of the recess 48 adjacent the diametrical open side 58of the ram block 32. The function of the seal member 62 so formed willbe explained hereafter.

Continuing with respect to FIG. 4, the lower edge 70 of the face plate52 forming a part of the ram block 32 forms a shearing blade to coactwiththe shearing blade member 44 of the second ram assembly 36 when theram assemblies 26 and 36 are moved to the closed position as shown inFIG. 5. Thus, an advantage of a separate face plate 52 secured to theram block 32 rather than forming the face plate 52 integrally or inunibody construction of the ram block 32 is that the face plate 52 maybe unbolted from the main portion of the ram block 32. The dull edge 70may thus be sharpened or a new face plate 52 added as part of the ramblock 32.

Continuing now with respect to FIGS. 3 and 4, the second ram assembly 36is provided with a ram block holder 38 of semi-circular configurationhaving a substantially concentric, semi-circular, upwardly openingrecess 42 on the upper side thereof. A semi-circular ram block 40 issecured, such as by a bolt 41 or other suitable means, within the recess42 of the ram block holder 38. A shearing blade member 44 is securedsuch as by means of a plurality of bolts 72 to and along the diametricalopen side of the ram block holder 38. The shearing blade member 44 isadapted to coact with the ram block 32 (and more particularly the loweredge 70 thereof) of the first ram assembly 26 to shear a drill string(i.e., the well string 20 of FIGS. 1 and 2) and is further adapted aftersuch shearing action to sealingly engage the seal member 62 of the firstram assembly 26 when the ram assemblies 26 and 36 are moved to theclosed position. In such position, a recess 84 (as best shown in FIG. 9)accommodates the sheared pipe 20 as shown in FIG. 2. A seal member 46similar to that of the seal member 36 is disposed along and between thecircular ports of the holder 38 and the block 40.

The ram block holders 28 and 38 of the ram block assemblies 26 and 36,respectively, are provided with means for actuating the assembliesclosingly toward and openingly away from each other within the chambers22 and 24 of the body member 16 as shown in FIGS. 1 and 2. While theactuating means are not shown in the drawings, it will be understood bythose skilled in the art that means may include hydraulic systems as arewell known. In addition, the actuating means includes slots 74 formed inthe ram block holders 28 and 38 in order to engage suitable piston meansas will become apparent to those skilled in the art. As shown in FIG. 9,the slots 74 are formed within arcuate shaped extensions 76 of the ramblock holders 28 and 38.

With reference primarily to FIG. 4, discussion being pertinent also toFIGS. 5 and 6, it is preferred that the upwardly opening recess 30 onthe upper side of the ram block holder 28 of the first ram assembly 26forms and is formed about an upwardly extending longitudinalprotuberance 76 along the diametrical open side of the ram block holder28. As shown in best detail in FIG. 6, the protuberance 76 matinglyengages surfaces 7 and 80 of the downwardly opening recess 48 of the ramblock 32. This construction in effect allows a dovetailing of structuralmembers to provide extra support for compressingly engaging the sealmember 62 disposed within the recess 48 which is substantially parallelto but spaced from the diametrical open side or face 50 of the ram block32. The elongate resilient strip portion of the seal 62 is suitablymounted within the recess 48 such that it engages the protuberance 76 ofthe ram block holder 28 on at least one side and engages the recess 48on at least another side. As shown in FIG. 6, the wall 56 of the recess48 nearest the diametrical open side 50 of the ram block 32 tapersoutwardly and downwardly and the elongate resilient strip portion of theseal 62 is of a configuration conforming to the surfaces of the recessthat it contacts.

With reference to FIG. '7, another embodiment of the first ram assembly26 is shown wherein the ram block holder 28 does not have aprotuberance. Thus, as shown in FIG. 7, the ram block holder 28 simplysup ports the ram block 32 and the recess 48 alone accommodates the sealmember 62.

FIG. 8 illustrates yet another embodiment of the first ram assemblywherein the seal member 62 is provided with a supporting plate 66 thatis flush with the sealing surface 68 of the resilient portion of theseal member 62. In such embodiment, lateral movement of the protuberance76 of the holder 28 relative to the block 32 forces the resilientportion of the seal member 62 into sealing engagement with the shearingblade 44 of the second ram assembly 36.

With respect to FIGS. 4, 5, 6 and 7, slightly varying embodiments of theelongate metal supporting plate 66 are shown wherein in each instancethe plate 66 is nevertheless embedded or molded in the strip ofresilient material forming the bulk of the strip member 62. In eachembodiment, the metal supporting plate 66 is adapted to pressinglyengage the shearing blade member 44 of the second ram assembly 36 whenthe ram assemblies 26 and 38 are moved to the closed position. As shownin FIG. 5, when the metal supporting plate 66 engages the shearing blade44, the resilient material of the seal member 62 is forced intocompressive engagement with the upper surface of the shearing blade 44,the compressive forces being indicated by the arrow 82 shown in FIG. 5.Such compressive action greatly strengthens the seal between the sealmember 62 and the shearing blade 44 insuring against leakage of any wellfluid upwardly between the ram assemblies 26 and 38. A seal 85 may beprovided within an appropriate recess within the ram block 46 to insureagainst leakage between the shearing blade 44 and the ram block 40, theseal 85 preferably being integrally formed with the seal member 46.

Referring once again to the seal members 34 and 46 of the first andsecond ram assemblies 26 and 36, respectively, the seal members 34 and46 are provided with half-ring reinforcing bars 56 preferably formed ofsteel which are molded in the semi-circular or half-ring strips ofresilient material that form the seals 34 and 66. The primary functionof the half-ring reinforcing bars 56 is to restrict and control squeezeimposed on the seals 34 through limited movement of the ram blocks 32and 40 within the ram block holders 28 and 36, respectively, when theram assemblies 26 and 36 are closed. Thus, the seal members 343 and d6effectively seal against fluid leakage between the ram blocks and ramblock holders of the ram assemblies 26 and 36, as well as between ramassemblies 26 and 36 and the upper inside face of ram chambers 22 and24. The sealing function is accomplished without the resilient materialof the seal members 34 and 46 excessively creeping or otherwise workingout of the space between the ram blocks and the ram block holders.

In operation, when it is desired to actuate the blowout preventer orcontrol gate apparatus of the present invention, the pipe ram assemblyI4 is moved into engagement with the drill pipe or well string 26 asshown in FIGS. 1 and 2. The ram assemblies 26 and 36 which are in theopen position as shown in FIG. I are moved to the closed position asshown in FIG. 2. During the closing operation, the shearing blade 44 ofthe holder 38 and the face 56 (FIG. 4) of the ram block 32 move towardeach other to flatten the pipe 26 as shown in FIG. 2. As the pipe 26 isflattened, it is cut by the blade 44 in shearing coaction with the loweredge '76 (FIG. 4) of the ram block 32 which also forms a shearing blade.

As the closing movement of the ram assemblies 26 and 36 continues, theshearing blade member 44 gradually engages the bottom side of thesupporting plate 66 of the seal member 62 as best shown in FIG. 5. Whenthe fully closed or engaged position of the ram assemblies 26 and 36 isreached as shown in FIG. 5, the supporting plate 66 is lifted upwardthereby generating a squeeze of the resilient or rubber portion of theseal 62 which results in increased compression (as shown by the arrow 82in FIG. 5) of the rubber in the sealing area designated by the referencecharacter 68 in FIGS. 4 and 5..

As shown in FIG. 4, a bore 35 is provided within the ram block holder 28to accommodate the bolt 33 that securably engages the ram block 32. Asimilar bore 43 is provided within the ram block holder 36 toaccommodate the bolt 41. The bores 35 and 43 are sufficiently largerthan the bolts 33 and 41, respectively, to allow limited lateralmovement of the ram blocks 32 and 46 relative to the ram block holders23 and 36, respectively. With regard to FIG. 6, upon closure of the ramassemblies, such lateral movement will create a gap between theprotuberance 76 of the holder 23 and the surface 78 of the ram block 32,the gap not being shown in the drawings.

It should be noted that additional compression of the rubber orresilient portion of the seal member 62 as indicated by the arrow 62 inFIG. 5 takes place due to 7 limited lateral movement of the ram block 32in the ram block holder 28 upon closing engagement of the ram assembly26 with the assembly 36. Because of this limited lateral movement, therubber or resilient portion of the seal 62 is squeezed between theprotuberance 76 of the holder 28 as shown in FIG. 6 and the taperedsurface 56 of the recess 48 of the ram block 32, also as shown in FIG.6. The tapered surface 56 in effect projects the squeezing thrust towardthe sealing area 68 of the seal 62. The increased compression of theresilient portion of the seal 62 strengthens or tightens the sealingcontact of the seal member 62 in the sealing area 68 of the seal 62 whenit engages the upper surface of the shearing blade 46 as shown in FIG.6.

After the drill pipe has been sheared, as shown in FIG. 2, the closingmotion of the ram assemblies 26 and 36 continues until the face 36 ofthe ram block 32 meets and abuts the divided face 62 of the ram block 46as best shown in FIG. 9. As shown in FIG. 3, the blade 44 will then bein the position indicated by the dotted outline 64a. In the closedposition, the upper portion of the cut drill pipe 26 as shown in FIG. 2is pushed between the ram block 32 and 46 into a recess 86 of the ramblock 46, the recess 36 of the ram block 40 being best shown in FIG. 9.Thus, the drill pipe 26 need not be raised or otherwise manipulated inorder for the ram assemblies 26 and 38 to effect a complete seal withinthe control gate body. Also as may be seen in FIG. 2, the lower portionof the cut drill pipe may move to a position between the shearing blade44 and the ram block holder 28, again obviating any necessity ofmanipulation of the cut drill pipe to effect a seal.

The present invention, therefore, is well adapted to carry out theobjects and attain the ends and advantages mentioned as well as othersinherent therein. While a presently preferred embodiment of theinvention has been given for the purpose of disclosure, numerous changesin the detail of construction and the combination, shape, size andarrangement of parts may be resorted to without departing from thespirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. A blowout preventer including,

a. a body member having a bore therethrough for reception of a drillstring and having opposed ramreceiving chambers in a plane normal tosaid bore,

b. a first ram assembly in one of said ram-receiving chambers, the firstram assembly comprising,

i. a ram block holder having an upwardly opening recess on the upperside,

ii. a ram block secured within the recess of the holder (b) (i), saidram block having a downwardly opening recess formed on the lower sidethereof along but spaced from an open side of said ram block,

iii. a first seal member disposed between the holder (b) (i) and the ramblock (b) (ii), and

iv. a second seal member disposed within the downwardly opening recessof the ram block (b) (ii), and

c. a second ram assembly in the other of said ramreceiving chambers, thesecond ram assembly comprising,

i. a ram block holder having an upwardly opening recess on the upperside,

ii. a ram block secured within the recess of the holder (b) (i),

iii. a shearing blade member secured to and projectingly disposed alongan open side of the ram block holder (c) (i) adapted to coact with theram block (b) (ii) of the first ram assembly (b) to shear a drill stringand further adapted after said shearing action to sealingly engage thesecond seal member (b) (iv) of the first ram (b), when the rams (b) and(c) are moved to the closed position, and

iv. a seal member disposed between the holder (c) (i) and the block(ii), and

d. means for actuating said ram assemblies closingly toward andopeningly away from each other in the chambers thereof normal to thebore of the body member (a).

2. The invention of claim 1 wherein the lower edge of the open side ofthe ram block (b) (ii) forms a shearing blade to coact with the shearingblade member (c) (iii) of the second ram assembly (0) when the rams (b)and (c) are moved to the closed position.

3. The invention of claim 1 wherein the second seal member (b) (iv) ofthe first ram assembly (b) extends at least the length of the open sideof the ram block (b) 4. The invention of claim 1 wherein the first sealmember (b) (iii) and (c) (iii) each comprise,

a half-ring strip of resilient material, and i a half-ring reinforcingbar molded in the resilient material yet exposed on one side forengagement with the ram blocks (b) (ii) and (c) (ii) respectively.

5. The invention of claim 1 wherein the second seal member (b) (iv)disposed within the downwardly opening recess of the ram block (b) (ii)comprises,

a strip of resilient material at least as long as the shearing blademember (c) (iii) and mounted within said recess so as to besubstantially flush with the lower surface of the ram block (b) (ii),and

an elongate metal supporting plate embedded in the strip of resilientmaterial and adapted to pressingly engage the shearing blade member (c)(iii) when the ram assemblies (b) and (c) are moved to the closedposition.

6. The invention of claim 5 wherein a portion of the resilient materialof the second seal member (b)(iv) is disposed between the elongate metalsupporting plate and the edge of the open side of the ram block (b)(ii)and is adapted to compressively engage the upper surface of the shearingblade member (c)(iii) when the rams (b) and (c) are moved to the closedposition.

7. A blowout preventer including,

a. a body member having a bore therethrough for reception of a drillstring and having opposed ramreceiving chambers in a plane normal tosaid bore,

b. a first rarn assembly in one of said ram-receiving chambers, thefirst ram assembly comprising,

i. a ram block holder of semi-circular configuration having asubstantially concentric semi-circular upwardly extending recess on theupper side formed about and forming an upwardly extending longitudinalprotuberance along the'diametrical, open side of the holder,

ii. a semi-circular rarn block secured within the recess of the holder(b)(i), said ram block having a downwardly opening, substantiallylongitudinal recess formed on the lower side thereof, a portion of therecess matingly engaging the protuberance of the holder (b)(i),

iii. a first seal member disposed along and between at least thecircular portions of the holder (b)(i) and the block (b)(ii), and

iv. a second seal member disposed within the recess of the lower side ofthe ram block (b)(ii) substantially parallel to but spaced form thediametrical open side of the block (b)(ii), and engaging theprotuberance of the ram block holder (b)(i),

c. a second ram assembly in the other of said ramreceiving chambers, thesecond ram assembly comprising,

i. a ram block holder of semi-circular configuration having asubstantially concentric, semi-circular, upwardly opening recess on theupper side,

ii. a semi-circular ram block secured within the recess of the holder(b)(i),

iiisa shearing blade member secured to the ram block holder (c)(i) so asto laterally project beyond the diametrical open side of the ram blockholder (c)(i) and adapted to coact with the ram block (b)(ii) of thefirst ram (b) to shear a drill string and further adapted after saidshearing action to sealingly engage the seal member (b)(iv) of the firstram (b) when the rams (b) and (c) are moved to the closed position, and

iv a seal member disposed along and between at least the circularportions of the holder (c)(i) and the block (c)(ii), and

d. means for actuating said ram assemblies closingly toward andopeningly away from each other in the rams thereof normal to the bore ofthe body member (a).

8. The invention of claim 7 wherein the lower edge of the diametricalopen side of the ram block (b)(ii) forms a shearing blade to coact withthe shearing blade member (c)(iii) of the second ram assembly when theram assemblies (b) and (c) are moved to the closed position.

9. The invention of claim 7 wherein the second seal member (b)(iv) ofthe first ram assembly (b) extends at least the length of thediametrical open side of the ram block (b)(ii).

10. The invention of claim 7 wherein the first seal members (b)(iii) and(c)(iii) each comprise,

a half-ring strip of resilient material, and

a half-ring reinforcing bar embedded in the resilient material yetexposed on one side for engagement with the ram block,

11. The invention of claim 7 wherein the second seal member (b)(iv)disposed within the recess of the lower side of the ram block (b)(ii)comprises,

an elongate resilient strip member at least as long as the shearingblade (c)(iii) and mounted within said recess such that it engages theprotuberance of the ram block holder (b)(i) on at least one side and therecess of the ram block (b)(ii) on at least another side, and

an elongate metal supporting plate embedded longitudinally in theresilient strip member and adapted to pressingly engage the shearingblade member (c)(iii) when the rams (b) and (c) are moved to the closedposition.

12. The invention of claim 11 wherein a portion of the resilientmaterial of the second seal member (b)(iv) is disposed between theelongate metal supporting plate and the edge of the diametrical openside of the ram block (b)(ii) and is adapted to compressively engage theupper surface of the shearing blade member (c)(iii) when the rams (b)and (c) are moved to the closed position.

13. The invention of claim 12 wherein,

in the downwardly opening, substantially longitudinal recess formed onthe lower side of the ram block b)( ii), the wall of the recess nearestthe diametrical open side of the ram block (b)(ii) tapers outwardly anddownwardly, and

the elongate resilient strip member is of a configuration substantiallyconforming to said recess.

14. In a blowout preventer having a body member having a boretherethrough for reception of a drill string and having opposedramreceiving chambers in a plane normal to said bore,

b. a first ram assembly in one of said ram-receiving chambers, the firstram assembly comprising,

i. a ram block holder of semi-circular configuration,

ii. a semi-circular ram block,

iii. a first seal member disposed along and between at least thecircular portions of the holder (b)(i) and the block (b)(ii),

c. a second ram assembly in the other of said ramreceiving chambers, thesecond ram assembly comprising,

i. a ram block holder of semi-circular configuration having asubstantially concentric, semi-circular upwardly opening recess on theupper side,

ii. a semi-circular ram block secured within the recess of the holder(b)(i),

iii. a shearing blade member secured to the ram block holder (c)(i), and

iv. a seal member disposed along and between at least the circularportions of the holder (c)(i) and the block (c)(ii), and

d. means for actuating said ram assemblies closingly toward andopeningly away from each other in the chambers thereof normal to thebore of the body member (a),

the improvement in the first rarn assembly wherein,

e. in the ram block holder (b)(i), a concentric semicircular, upwardlyopening recess on the upper side is formed about and forms an upwardlyextending longitudinal protuberance along the diametrical open side ofthe holder,

f. in the ram block (b)(ii), the ram block being secured within therecess of the holder (b)(i), said ram block has a downwardly opening,substantially longitudinal recess formed on the lower side thereof, aportion of the recess matingly engaging the protuberance of the holder(b)(i), and

a second seal member is disposed within the recess of the lower side ofthe ram block (b)(ii) substantially parallel to but spaced from thediametrical open-side of the ram block (b)(ii) and engaging theprotuberance 0f the ram block holder (b)(i), and the improvement in thesecond ram assembly wherein,

h. the shearing blade member (c)(iii) is secured to the ram block holder(c)(i) so as to laterally project beyond the diametrical open side ofthe ram block holder (c)(i) and is adapted to coact with the ram block(b)(ii) of the first ram assembly (b) to shear a drill string andfurther adapted after said shearing action to sealingly engage thesecond seal member (g) of the first ram assembly (b), when the ramassemblies (b) and (c) are moved to the closed position.

15. The invention of claim 14 wherein the diametrical open sides of theram block (c)(ii) and the ram block holder (b)(i) are recessed toaccommodate a sheared drill string.

16. The invention of claim 14 wherein the second seal member (g)disposed within the recess of the lower side of the ram block (b)(ii)comprises,

an elongate resilient strip member at least as long as the shearingblade (c)(iii) and mounted within said recess such that it engages theprotuberance of the ram block holder (b)(i) on at least one side andengages the recess of the ram block (b)(ii) on at least another side,and

an elongate metal supporting plate embedded and adapted to pressinglyengage the shearing blade member (c)(iii) when the ram assemblies (b)and (c) are moved to the closed position, a portion of the strip ofresilient material being disposed between the elongate metal supportingplate and the edge of the diametrical open side of the ram block (b)(ii)and being adapted to compressingly engage the upper surface of theshearing blade member tion substantially conforming to said recess.

18. The invention of claim 16 wherein the ram blocks (b)(ii) and (c)(ii)are secured to the ram block holders (b)(i) and (c)(i), respectively bymeans providing limited lateral movement of the ram blocks relative tothe ram block holders such that force may be exerted by the protuberanceof the ram block holder (b)(i) against the second seal member (g).

1. A blowout preventer including, a. a body member having a boretherethrough for reception of a drill string and having opposedram-receiving chambers in a plane normal to said bore, b. a first ramassembly in one of said ram-receiving chambers, the first ram assemblycomprising, i. a ram block holder having an upwardly opening recess onthe upper side, ii. a ram block secured within the recess of the holder(b) (i), said ram block having a downwardly opening recess formed on thelower side thereof along but spaced from an open side of said ram block,iii. a first seal member disposed between the holder (b) (i) and the ramblock (b) (ii), and iv. a second seal member disposed within thedownwardly opening recess of the ram block (b) (ii), and c. a second ramassembly in the other of said ram-receiving chambers, the second ramassembly comprising, i. a ram block holder having an upwardly openingrecess on the upper side, ii. a ram block secured within the recess ofthe holder (b) (i), iii. a shearing blade member secured to andprojectingly disposed along an open side of the ram block holder (c) (i)adapted to coact with the ram block (b) (ii) of the first ram assembly(b) to shear a drill string and further adapted after said shearingaction to sealingly engage the second seal member (b) (iv) of the firstram (b), when the rams (b) and (c) are moved to the closed poSition, andiv. a seal member disposed between the holder (c) (i) and the block (c)(ii), and d. means for actuating said ram assemblies closingly towardand openingly away from each other in the chambers thereof normal to thebore of the body member (a).
 2. The invention of claim 1 wherein thelower edge of the open side of the ram block (b) (ii) forms a shearingblade to coact with the shearing blade member (c) (iii) of the secondram assembly (c) when the rams (b) and (c) are moved to the closedposition.
 3. The invention of claim 1 wherein the second seal member (b)(iv) of the first ram assembly (b) extends at least the length of theopen side of the ram block (b) (ii).
 4. The invention of claim 1 whereinthe first seal member (b) (iii) and (c) (iii) each comprise, a half-ringstrip of resilient material, and a half-ring reinforcing bar molded inthe resilient material yet exposed on one side for engagement with theram blocks (b) (ii) and (c) (ii) respectively.
 5. The invention of claim1 wherein the second seal member (b) (iv) disposed within the downwardlyopening recess of the ram block (b) (ii) comprises, a strip of resilientmaterial at least as long as the shearing blade member (c) (iii) andmounted within said recess so as to be substantially flush with thelower surface of the ram block (b) (ii), and an elongate metalsupporting plate embedded in the strip of resilient material and adaptedto pressingly engage the shearing blade member (c) (iii) when the ramassemblies (b) and (c) are moved to the closed position.
 6. Theinvention of claim 5 wherein a portion of the resilient material of thesecond seal member (b)(iv) is disposed between the elongate metalsupporting plate and the edge of the open side of the ram block (b)(ii)and is adapted to compressively engage the upper surface of the shearingblade member (c)(iii) when the rams (b) and (c) are moved to the closedposition.
 7. A blowout preventer including, a. a body member having abore therethrough for reception of a drill string and having opposedram-receiving chambers in a plane normal to said bore, b. a first ramassembly in one of said ram-receiving chambers, the first ram assemblycomprising, i. a ram block holder of semi-circular configuration havinga substantially concentric semi-circular upwardly extending recess onthe upper side formed about and forming an upwardly extendinglongitudinal protuberance along the diametrical, open side of theholder, ii. a semi-circular ram block secured within the recess of theholder (b)(i), said ram block having a downwardly opening, substantiallylongitudinal recess formed on the lower side thereof, a portion of therecess matingly engaging the protuberance of the holder (b)(i), iii. afirst seal member disposed along and between at least the circularportions of the holder (b)(i) and the block (b)(ii), and iv. a secondseal member disposed within the recess of the lower side of the ramblock (b)(ii) substantially parallel to but spaced form the diametricalopen side of the block (b)(ii), and engaging the protuberance of the ramblock holder (b)(i), c. a second ram assembly in the other of saidram-receiving chambers, the second ram assembly comprising, i. a ramblock holder of semi-circular configuration having a substantiallyconcentric, semi-circular, upwardly opening recess on the upper side,ii. a semi-circular ram block secured within the recess of the holder(b)(i), iii. a shearing blade member secured to the ram block holder(c)(i) so as to laterally project beyond the diametrical open side ofthe ram block holder (c)(i) and adapted to coact with the ram block(b)(ii) of the first ram (b) to shear a drill string and further adaptedafter said shearing action to sealingly engage the seal member (b)(iv)of the first ram (b) when the rams (b) and (c) are moved to the closedposition, and iv a seal member disposed along and between at leasT thecircular portions of the holder (c)(i) and the block (c)(ii), and d.means for actuating said ram assemblies closingly toward and openinglyaway from each other in the rams thereof normal to the bore of the bodymember (a).
 8. The invention of claim 7 wherein the lower edge of thediametrical open side of the ram block (b)(ii) forms a shearing blade tocoact with the shearing blade member (c)(iii) of the second ram assembly(c) when the ram assemblies (b) and (c) are moved to the closedposition.
 9. The invention of claim 7 wherein the second seal member(b)(iv) of the first ram assembly (b) extends at least the length of thediametrical open side of the ram block (b)(ii).
 10. The invention ofclaim 7 wherein the first seal members (b)(iii) and (c)(iii) eachcomprise, a half-ring strip of resilient material, and a half-ringreinforcing bar embedded in the resilient material yet exposed on oneside for engagement with the ram block,
 11. The invention of claim 7wherein the second seal member (b)(iv) disposed within the recess of thelower side of the ram block (b)(ii) comprises, an elongate resilientstrip member at least as long as the shearing blade (c)(iii) and mountedwithin said recess such that it engages the protuberance of the ramblock holder (b)(i) on at least one side and the recess of the ram block(b)(ii) on at least another side, and an elongate metal supporting plateembedded longitudinally in the resilient strip member and adapted topressingly engage the shearing blade member (c)(iii) when the rams (b)and (c) are moved to the closed position.
 12. The invention of claim 11wherein a portion of the resilient material of the second seal member(b)(iv) is disposed between the elongate metal supporting plate and theedge of the diametrical open side of the ram block (b)(ii) and isadapted to compressively engage the upper surface of the shearing blademember (c)(iii) when the rams (b) and (c) are moved to the closedposition.
 13. The invention of claim 12 wherein, in the downwardlyopening, substantially longitudinal recess formed on the lower side ofthe ram block (b)(ii), the wall of the recess nearest the diametricalopen side of the ram block (b)(ii) tapers outwardly and downwardly, andthe elongate resilient strip member is of a configuration substantiallyconforming to said recess.
 14. In a blowout preventer having a bodymember having a bore therethrough for reception of a drill string andhaving opposed ram-receiving chambers in a plane normal to said bore, b.a first ram assembly in one of said ram-receiving chambers, the firstram assembly comprising, i. a ram block holder of semi-circularconfiguration, ii. a semi-circular ram block, iii. a first seal memberdisposed along and between at least the circular portions of the holder(b)(i) and the block (b)(ii), c. a second ram assembly in the other ofsaid ram-receiving chambers, the second ram assembly comprising, i. aram block holder of semi-circular configuration having a substantiallyconcentric, semi-circular upwardly opening recess on the upper side, ii.a semi-circular ram block secured within the recess of the holder(b)(i), iii. a shearing blade member secured to the ram block holder(c)(i), and iv. a seal member disposed along and between at least thecircular portions of the holder (c)(i) and the block (c)(ii), and d.means for actuating said ram assemblies closingly toward and openinglyaway from each other in the chambers thereof normal to the bore of thebody member (a), the improvement in the first ram assembly wherein, e.in the ram block holder (b)(i), a concentric semi-circular, upwardlyopening recess on the upper side is formed about and forms an upwardlyextending longitudinal protuberance along the diametrical open side ofthe holder, f. in the ram block (b)(ii), the ram block being securedwithin the recess of the holder (b)(i), said ram Block has a downwardlyopening, substantially longitudinal recess formed on the lower sidethereof, a portion of the recess matingly engaging the protuberance ofthe holder (b)(i), and g. a second seal member is disposed within therecess of the lower side of the ram block (b)(ii) substantially parallelto but spaced from the diametrical open side of the ram block (b)(ii)and engaging the protuberance of the ram block holder (b)(i), and theimprovement in the second ram assembly wherein, h. the shearing blademember (c)(iii) is secured to the ram block holder (c)(i) so as tolaterally project beyond the diametrical open side of the ram blockholder (c)(i) and is adapted to coact with the ram block (b)(ii) of thefirst ram assembly (b) to shear a drill string and further adapted aftersaid shearing action to sealingly engage the second seal member (g) ofthe first ram assembly (b), when the ram assemblies (b) and (c) aremoved to the closed position.
 15. The invention of claim 14 wherein thediametrical open sides of the ram block (c)(ii) and the ram block holder(b)(i) are recessed to accommodate a sheared drill string.
 16. Theinvention of claim 14 wherein the second seal member (g) disposed withinthe recess of the lower side of the ram block (b)(ii) comprises, anelongate resilient strip member at least as long as the shearing blade(c)(iii) and mounted within said recess such that it engages theprotuberance of the ram block holder (b)(i) on at least one side andengages the recess of the ram block (b)(ii) on at least another side,and an elongate metal supporting plate embedded and adapted topressingly engage the shearing blade member (c)(iii) when the ramassemblies (b) and (c) are moved to the closed position, a portion ofthe strip of resilient material being disposed between the elongatemetal supporting plate and the edge of the diametrical open side of theram block (b)(ii) and being adapted to compressingly engage the uppersurface of the shearing blade member (c)(iii) when the rams (b) and (c)are moved to the closed position.
 17. The invention of claim 16 wherein,in the downwardly opening substantially longitudinal recess (f) formedon the lower side of the ram block (b)(ii), the wall of the recess (f)nearest the diametrical open side of the ram block (b)(ii) tapersoutwardly and downwardly, and the elongate resilient strip member is ofa configuration substantially conforming to said recess.
 18. Theinvention of claim 16 wherein the ram blocks (b)(ii) and (c)(ii) aresecured to the ram block holders (b)(i) and (c)(i), respectively bymeans providing limited lateral movement of the ram blocks relative tothe ram block holders such that force may be exerted by the protuberanceof the ram block holder (b)(i) against the second seal member (g).